This type of measurement is usually done by periodic and automatic sampling in the pipe, and so that the measurement performed on the samples represents the composition of the whole batch of fluid (cargo), it is first of all necessary that this batch be homogenous in compliance with ISO standard 3171. Well, the components of such a mixture tend to separate from each other naturally at least when its velocity is slow, for example, less than 1 m/s. So a homogenizing device must come into play a little distance upstream from the point where the samples are taken. Moreover, the size of the droplets of the discontinuous phase is important for the measurement. In the case of a petroleum conduit also carrying a little water, it is necessary that the mixture arriving at the measurement device be of petroleum containing several water droplets per cm.sup.3 of mixture, with a droplet diameter of from 0.5 mm to 2 mm at the most.
Homogenizing may also be useful in the following cases:
when a pipe is carrying a multiphase fluid whose phases have the tendency to separate from each other (because of gravity, for example) and when this separation has a harmful effect upon operations and/or causes abnormal wear or corrosion of the conduits
upstream from the connecting point a secondary pipe supplying a user of the fluid carried, in order that this user will receive a product whose two phases are in the proper proportions
when it is desired, on-line, to mix two liquid components in orer to produce a product.
Various devices for homogenizing a fluid carried in a pipe are already known, for example in British Patent No. 2.303.963 (JISKOOT Autocontrol Ltd.) and European Patent No. 0060634 (Moore, Barrett and Redwood Ltd.).
The device in European Patent No. 0060634 includes the following elements which are shared, in terms of certain of their functions, by this known device and by the device according to the invention:
a tapping conduit (4) having a tapping opening in this carrier pipe (2) to suck off a fraction of the flow of the fluid to be homogenized, this opening being placed a zone which is enriched by gravity in the discontinuous phase, this zone being the top or bottom zone of this pipe according to whether the discontinuous phase is more dense or less dense than the continuous phase, respectively,
a circulating pump (6) installed at the output from the tapping conduit to circulate and pressurize the fluid which has been sucked off,
an injection conduit (8, 10, 12, 14, 16, 18) receiving the fluid pressurized in this way,
and injection nozzles (20, 22, 24, 26) fed by this injection conduit and forming, in this pipe, cross jets which create swirls to homogenize the said fluid carried, and each of these nozzles has an axis which is also the axis of the jet which it forms.
(The reference numbers or letters between parentheses refer to the examples shown on the appended figures)
This known device is particularly applicable for carrying petroleum mixed with water. If is the water which constitutes the so-called discontinuous phase. A certain homogenization can be obtained with the aid of this device, but
on the one hand, the power of the circulating pump must be high because of the necessity of injecting a flow which represents a relatively large fraction of the total flow so that the stirring induced will be sufficient,
and on the other hand, this device precludes dissociating the phase to be dispersed in droplets of well known and sufficiently tiny dimensions, which do not necessarily prevent a later very rapid decantation or coalescence of the drops of the discontinuous phase nor, consequently, the danger of distorting the measurement by sampling.
This is perhaps because this device was designed for homogenizing by stirring the mixture.
The purpose of the present invention is to build a simple device to make it possible to obtain a good homogenization with the following properties:
on the one hand, the size of the drops in the discontinuous phase is reduced,
on the other hand, the small drops formed in this way are well dispersed and their number per cm.sup.3 of mixture is relatively uniform,
and this is done without the power needed at the circulating pump being substantially greater than the power necessary for the operation of the known devices, and without the present device having a cumbersome longitudinal bulk.